1. Technical Field
The present invention relates to an optical device, a biological information detector, and similar devices.
2. Background Technology
A biological information measuring device measures human biological information such as, for example, pulse rate, blood oxygen saturation level, body temperature, or heart rate, and an example of a biological information measuring device is a pulse rate monitor for measuring the pulse rate. Also, a biological information measuring device such as a pulse rate monitor may be installed in a clock, a mobile phone, a pager, a PC, or another electrical device, or may be combined with the electrical device. The biological information measuring device has a biological information detector for detecting biological information, and the biological information detector includes a light-emitting element for emitting light towards a detection site of a test subject (i.e., a user), and a light-receiving element for receiving light having biological information from the detection site. Thus, a biological information detector or the biological information measuring device may have an optical device and be capable of detecting or measuring biological information. A common detector or a measuring device (or in a broader sense, an electronic device) other than a biological information detector or a biological information measuring device may also have an optical device.
In Patent Citation 1, there is disclosed a pulse rate monitor (or in a broader sense, a biological information measuring device). A light-receiving element (e.g., a light-receiving element 12 in FIG. 16 of Patent Citation 1) of the pulse rate monitor receives light reflected at a detection site (e.g., dotted line in FIG. 16 of Patent Citation 1) via a diffusion reflection plane (e.g., reflecting part 131 in FIG. 16 of Patent Citation 1). In an optical probe 1 in Patent Citation 1 (or in a broader sense, a biological information detector), a light-emitting element 11 and the light-receiving element 12 overlap with respect to a plan view, and the size of the optical probe 1 is reduced.
JP-A 2004-337605 (Patent Citation 1) is an example of the related art.